This application is a competing renewal. The original project concerned new fast magnetic resonance imaging (MRI) techniques for improved diagnosis of abdominal tumors. Significant progress was made in developing several fast-scan methods that produce high-quality T2-weighted abdominal images in a breath-hold. The focus of this competing renewal is on new MR methods that take the next step beyond tumor detection---the guidance of tumor biopsies and other interventional procedures using MR. The project title has been modified to reflect this change in focus. The aims of this project are to 1) design and implement a real-time, interactive (RTI) MRI system tailored for interventional procedures, 2) develop and integrate into the RTI system new sequences that provide useful image contrast for interventional procedures; and 3) evaluate this new MR interventional system on phantoms and patients. The research plan includes substantial technical development of a versatile RTI MRI platform, studies of improved MR acquisition methods (e.g., steady-state free precession, fast spin echo, and color flow), and systematic tests to validate the performance of the resultant system. A research team with extensive technical and clinical expertise has been assembled for this project. This expertise, along with the state-of-the-art scanners available, make Stanford University an ideal environment to carry out this project.